The concept of converting one electromagnetic wavelength radiation to a different wavelength radiation by the use of a dye-containing polymeric sheet, and then transmitting this different wavelength to an edge surface of the polymeric sheet for detection is known in the art, as is exemplified below.
U.S. Pat. No. 4,227,939 relates to a solar collector for receiving light on one surface, trapping the light in a substrate by internal reflection, and then carrying the light to the edge of the substrate, where the light is emitted into photo voltaic cells. The substrate contains a fluorescent dye, and the substrate can be an acrylic polymer with the dye present as a layer on the back surface of the substrate.
U.S. Pat. No. 4,262,206 relates to a radiation converter wherein radiation is absorbed by a fluorescent dye and re-emitted as a longer wavelength radiation. This longer wavelength radiation is trapped within a substrate member, and is internally reflected by its boundary surfaces towards its ends, whereat the longer wavelength radiation leaves the substrate member, to be detected by an external radiation detector.
U.S. Pat. No. 4,110,026 discloses a fluorescent light concentrator having a fluorescent source that is surrounded on all sides but one by a metal reflector, and with a flat, planar, plastic member containing fluorescent dyes located on the one side of the source. Light is transmitted through the plastic member to end surfaces, at which the light is discharged onto the photoconductor of a xerographic reproduction device. At one location, the light is used to provide pretransfer illumination, and at a second location the light is used to provide preclean illumination. The plastic member is located within the loop of a belt photoconductor, to thereby backlight the photoconductor. The surfaces of the plastic member which do not collect or emit light are covered with a reflective material, to thereby reflect stray light back into the plastic member. It is stated that, "a dye should be chosen which will effervesce to produce light having substantial components in a region of the spectrum where a photoconductor peaks in response or sensitivity." It is also stated, "that the arrangement could be used as an interframe erase lamp".
U.S. Pat. No. 4,460,939 relates to a device for providing a line of light in which a light source is disposed on one focal line of an elliptical reflecting surface, with a plate-like light guide being placed at the second focal line of the elliptical surface. A reflector substantially surrounds the light source, the reflector being formed to have one-half of an elliptical surface and one-half of a cylindrical surface. The result is to concentrate light produced by the light source at the collecting focal line. The light source provides a line of light for an optical reader.
U.S. Pat. No. 4,467,208 relates to a radiation sensor containing a fluorescing material. The exterior surface of the sensor comprises a transparent material, having a core that contains the fluorescent material. Fluorescent light that is produced is conducted to a photosensitive surface.
U.S. Pat. Nos. 4,383,973 and 4,492,778 are of general interest in that they describe the making of dyestuff light collectors.
While devices of the type described above are generally acceptable for their intended purposes, a need remains in the art to provide an efficient light source whose external beam provides a brightness that is a multiple of the brightness of the internal light source, wherein the cross sectional shape of the external beam can easily be shaped as desired, and wherein the shape and size of the originating light source and the external beam can be independently and easily conformed to the dimensional constraints that are provided by the design and construction of a light utilization in which the present invention finds utility.